Mud Motor Bearing Assembly With Hydrodynamic Wedge Rings

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Solution Overview

Problem

Conventional mud motors have limited bearing life due to harsh drilling conditions, leading to frequent failures and high maintenance costs, as they are not tolerant of abrasives and require complex repairs.

Innovation Solution

A simplified mud motor bearing assembly with a single bearing section using wedge-shaped projections and wear-resistant inserts, capable of handling both radial and axial loads, which forms a hydrodynamic fluid film for reduced friction and enhanced durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional radial and thrust bearings are used to support the drive shaft, then radial and axial loads can be restricted, but bearing life is limited due to abrasive wear from drilling fluid

Engineering Contradiction:
Improvebearing lifeVSAvoidabrasive wear from drilling fluid
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent removes the traditional bearing components (radial bearings and thrust bearings) from the mud motor assembly. Instead of using conventional bearings that are susceptible to abrasive wear from drilling fluid, the invention extracts the bearing function entirely and replaces it with a seal assembly that provides both sealing and bearing capabilities, thereby eliminating the harmful abrasive wear effect

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The seal assembly is designed to perform multiple functions simultaneously: it provides sealing between the stator and rotor while also supporting radial and axial loads. This multi-functional design replaces the need for separate radial bearings and thrust bearings, improving reliability by using a single component that is not susceptible to abrasive wear from drilling fluid

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If multiple bearing sets (upper radial, thrust, lower radial) are used to support the drive shaft, then radial and axial movement is restricted, but device complexity increases

Engineering Contradiction:
Improvedrive shaft supportVSAvoidnumber of bearing sets
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the functions of upper radial bearings, thrust bearings, and lower radial bearings into a single seal assembly. This unified component provides both radial support and axial thrust support while maintaining sealing functionality, thereby reducing device complexity by eliminating multiple separate bearing sets

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The seal assembly is designed as a universal component that simultaneously performs sealing, radial load support, and axial load support functions that were previously distributed across multiple specialized bearing components, simplifying the overall device structure

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Force

If conventional bearings are used in harsh drilling conditions, then load support is provided, but maintenance frequency increases due to limited bearing life

Engineering Contradiction:
Improveload support capabilityVSAvoidbearing service life
Core Design Contradiction:
ForceVSDuration of action of moving object

Solution Approach 1:

The patent extracts the conventional bearing components from the system and replaces them with a seal assembly that is not susceptible to the same abrasive wear mechanisms. This substitution maintains load support capability while significantly extending service life in harsh drilling conditions by eliminating the wear-prone bearing surfaces

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention employs a seal assembly that is designed to be more durable than conventional bearings in abrasive environments. By using components that are not susceptible to abrasive wear from drilling fluid, the service life is extended, reducing maintenance frequency and associated costs

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The bearing assembly significantly extends operational life, reduces maintenance complexity, and lowers costs by distributing thrust loads evenly across multiple bearing rings, minimizing wear and the need for specialized tools.

Implementation Method 1

capable of handling both radial and axial loads, which forms a hydrodynamic fluid film for reduced friction and enhanced durability

Methodology Applied
Scientific EffectHydrodynamic lubrication: Lubrication

Data Source

PatentEP2847477B1Mud motor bearing assembly and method
Publication Date: 2022.07.06 RIVAL DOWNHOLE TOOLS LC
  • EP2847477B1 patent drawingFigure 1A~1B
  • EP2847477B1 patent drawingFigure 2A~2B
  • EP2847477B1 patent drawingFigure 3~8

AI summary

A mud motor bearing assembly for use in drilling a hydrocarbon well. The bearing assembly includes a bearing section containing stationary bearing rigs and rotating bearing rings in stacked arrangement. The bearing rings have wedge-shaped projections. The wedge-shaped projections of two adjacent stationary bearing rings form a recess to accommodate the projection of a rotating bearing ring in sliding engagement. The bearing assembly is capable of bearing both radial and axial loads.